A group of protesters is calling for the resignation of Cook County State's Attorney Anita Alvarez.

They are upset that the state's attorney's decided not to prosecute a Chicago police officer who shot and killed a man in 2011.

"We want control over our police. No justice. No peace," they chanted.

They're unhappy with the state's attorney - more specifically her decision not to prosecute Chicago Police Officer Gildardo Sierra. In a June 2011 domestic disturbance call, Sierra gave chase to Flint Farmer, on foot and shot him seven times. A dash cam from another squad arriving at the scene shows Officer Sierra firing three shots at close range, hitting a wounded Farmer already on the ground.

Sierra claimed to fellow officers that he believed Farmer had a gun. It turned out to be a burgundy cell phone.

State's Attorney Alvarez concluded, in a letter to the police superintendent earlier this week, that Sierra's actions were not criminal, that his belief Farmer had a gun, "although mistaken was nevertheless reasonable" and that prosecutors wouldn't be able to prove otherwise in spite of the "tragic results."

"I'm terribly upset. I'm very angry," said Emmet Farmer, Flint Farmer's father, who was among those protesting outside the county administration building Friday afternoon. He and others here say they can see no justification for an officer to fire a total of 16 shots at someone who's running away, who is hit four times, falls to the ground on his stomach, and is shot three times in the back.

"One time, two times, three times. That don't make any sense," Emmet Farmer said.

The state's attorney did not respond to the protesters but said in her letter to Chicago police that the investigation was exhaustive and that it would not have been possible to prove beyond reasonable doubt that Sierra's use of deadly force was unjustified.

"Our criminal justice system is full of prosecutors looking at winning and losing instead of seeking justice. This young man was shot three times in the back, and that's a human rights violation," said Christa Noel, Women's All-points Bulletin.

Flint Farmer's death led to a civil lawsuit, which the city settled out of court earlier this year for $4 million. Officer Sierra - before Flint Farmer's death - was involved in two other shootings, one of them fatal. After the Farmer shooting, Sierra was stripped of his police powers and given administrative duties. That continues. Whether he faces departmental discipline is up to the Independent Police Review Authority and the superintendent.